Syringe



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A ril 2B, 3936. F. s. DICKINSON SYRINGE Filed Nov. 13, 1951 WITNESS ATTCRNEYS Patente A r. 21, 1936 2,037,768

UNITED STATES PATENT OFFICE SYRINGE Fairleigh S.,Dickinson, Rutherford; N. J.

Application November 13, 1931, Serial No. 574,764

2 Claims. (01. 128-215)- The invention relates to syringes and morepartoward theaxis of the barrel, and the obliquely ticularly to syringes of the type comprising a and outwardly extending terminal portions l2. glass barrel. and plunger. The object ofthe irr- The portions H and I2 include the friction face vention is to provide simple, inexpensive, and effi- Iii-which, when in contact with the outer surface 5 cient means for producing by a single instrumenoi the plunger, exercises a moderate braking eftality difierential braking. effects against the feet, and the portion I4, which represents a cam plunger, such that the plunger will be under modface co-acting with the enlargement 6 of the crate braking influence during the major part of: plunger. In. the described construction it will be itsmovement, while the braking strain is accen-' noted that the parts ll, I2, l3, and I4 consti- 10 tuated during the final movement of theplunger' tute upwardly rising extensions whose movements 10 to its fully seated positionin the barrel. Accordare limited to movements away from or at right ing to the present invention the same structural angles to the axis of the plunger and that the elements are used for the establishment of the parts thereof which have frictional activities, I3 twodifferent typesof braking effect- The moder-- and I4, are so-arranged and positioned that they ate braking effect will enable the physician or will operate as brakes against the plunger and as 15 user to set or maintain the plunger at any desired a means for normally preventing the plunger point with respect to the dosage to be admitted from contacting with the nozzle end of the barrel to the syringe or to be ejected therefrom. The becauseof the tendency of the free terminal seemore intensified: braking effect will not prevent tions to -move toward each other. and because the the plunger from being fully seated the barrel, resilience of their supporting components allows 20 but will, in the normal carrying position of the them to move apart, under forcible depression of. syringe, space the bottom of. the plunger from the e p r ad and to raise e p e e bottom of the barrel and prevent/impacts dueto the depressing force is withdrawn. It will further vibration, or the like, from breaking offthe ejec-- be. noted that these upw y rising extensions tion end of the barrel. ll, I2, |3,.and I4 are integrally connected with 25 The invention is shown in the accompanying the barrel-embracing portion 8 by integral strip drawing in which Fig. 1 is: an elevation partly in p r Of which the p t 9 e nds 011tsection showing the syringe with the parts in wardlyfrom the barrel beneath its ledge 4, formtheir normal position as carriedv by the physician inga resilient hinge where 9 and 8 join. Thence or user. Fig. 2 is a similar View showing the the strips extend upwardly around the ledge and 30 plunger partially drawn out. of the barrel. Fig. back again over the top of the ledge as at ID in 3. is a sectional view showing the position of the a direction toward the axis of the plunger. The par-ts when. the plunger is fully seated and the full result of this arrangement is that the normal dose previously contained in the. barrel has been braking action of the upwardly raising extensions ejected. Fig. 4 is a sideview of. the upper part'of l'l' of-the clip, in any intermediate position of the 35 Fig. 1 and Fig. 5 is a sectional view on. line 5--5 plunger with relation to the barrel (as indicated of Fig. 2. in Fig. 2'), is; a function of theresiliency of the In the drawing, l represents the usual barrel extensions H While, when the extensions ll of having an ejecting end 2', a duct 3, and, at the the clipare forcibly pressed apart (as shown in 40 upper portion, a ledge or flange 4. The plunger Fig. 3:), the resilience of the fingers II will be 40 5 is provided with an enlargement or head 6-. As reinforcedby the resiliency of the hinge connecshown in Fig. 5 the ledge 4 comprises two section between parts 9' an'd8'. When the operator tions 4a which extend further from. the axis offthe removes hisfinger from the plunger head 6, the cylinder than the straight sided sections 41%.. The parts being in the position shown in Fig- 3, the

45 under sides of the portions4a afford anabutment combined resilience of the hinge connection re- 45 for the. index and middle-fingersof the operator ferred to and of the upward extensions H has while his thumb rests on the head 6' in ejecting suflicient pressing capacity to restore the plunger fluid from the syringe. The parts 411 of theledge to-thepositionshown in Fig. 1, after which, as the are used in connection with the clip 1. The clip. plunger is raised. to a position such as indicated I is an integral piece ofresilient metal stamped. in Fig.2, theiresiliency of the extensions Il' alone 50 into the shape. shown in the drawing and comis thereafter sufficient to supply thenormal brakprising the barrel-embracing portion 8, the poring' eifects which hold the plunger in any more 'tion 9 which engages the under surface. of the withdrawn position. In any event the extenflange 4, the portion II] which engages the upper sions. It at their free terminal regions not only surface of the flange 4', the spring fingers I lfiexed function constantly in all positions of the plung- 5 er but also do the whole of a diverse character of service, i. e. braking, cushioning, and lifting and accomplish this by the capacity of the extensions to move toward and to be moved away from each other always toward and away from the axis of the plunger and not in parallelism to such axis.

In the manufacture of glass plungers, one end of a glass tube is heated, its end closed, and the workman then blows a bulb at the closed softened end of the tube. This bulb is reintroduced to the flame, softened thereby, and the Workman then closes a tool upon the softened bulb, the tool forming the head 5 and the neck 15. When the glass is cooled, the workman tools it to close the other end in the flame and presses the bottom against a fiat surface. When the thus formed plunger has cooled, the outer surface of its plunger section is ground. This method of forming the plunger results in variations in the length of the ground section as well as the over-all length of the plunger. These variations are generally within narrow limits of one or two millimeters for plungers adapted to fit the same size of barrels. The construction of the clip I, particularly with respect to the cam faces I4, is consequently such as to function in the intended fashion, irrespective of whether the distance between the under side of the enlargement 6 of the plunger and the bottom fiat surface of the plunger is slightly greater or less than the particular distance illustrated in the drawing. In other words, the clip I is so made that it will fit any syringe of the same type and do its work properly, notwithstanding the usual variations in the length of the plungers. A feature not so apparent but of material importance is that the neck l5 of the plunger is not to be made as narrow as is now general practice, but shall at most be only slightly smaller than the cross section of the ground section of the plunger. This insures a continuance of the braking effect of the friction faces l3 after they leave the ground section of the plunger and pass the shoulder l5 and during the time that the friction faces l3 are in contact with the neck 15 before the cam faces l4 begin to be acted on by the underside of the plunger head 6. By making the neck 55 at best but slightly smaller than the ground section of the plunger, there is no sharp offset at the shoulder I B so that the braking effect of the friction faces l3 continues smoothly and without jump. In other words, the upper portion of the plunger is specially fashioned to minimize any sudden alteration in the braking effect of a braking instrumentality or clip which functions by virtue of the exercise of resilient pressure against the ground face of the plunger and may also at another stage of the operation rest against a smooth face of a portion of the neck, or vice versa, in succession.

It will be observed that when the parts are in the normal, inactive position shown in Fig. 1, the plunger is maintained out of contact with the ejecting end of the barrel and that irrespective of shocks, vibrations, rough transportation or the like, the plunger will be prevented from fully seating itself within the barrel and thereby protect the forward end of the barrel against breakage. When, however, it is desired to fill the syringe, the operator has but to place a slight additional pressure upon the head 6, causing the resilient fingers of the clip to be cammed aside as shown in Fig. 3, whereupon the plunger can be withdrawn to any desired point and the syringe correspondingly filled with fluid. As the plunger is withdrawn, say to the position shown in Fig. 2, the friction faces 13 of the resilient fingers I! will press against the outer surface of the plunger and exercise a moderate braking effect suflicient to maintain the plunger at any desired position in the barrel, in the absence of applied pressure on the head 6, so that the physician may lay down the syringe and subsequently pick it up again without fear that due to relative movement of the parts any change of the syringe has taken place. When it is now desired to empty the syringe, the thumb, pressing against the head 6, will cause the plunger to move down in the barrel and at the moment the position shown in Fig. l is reached, a slight additional pressure to overcome the accentuated braking effect of the cam faces I 4 of the fingers II will permit the cylinder to be readily and gently brought to the fully seated position shown in Fig. 3. After the syringe is cleaned and/or sterilized and redeposited in its case or in the physicians pocket, it will automatically assume and retain the condition shown in Fig. l where, on the one hand, the plunger cannot fall or slide out of the barrel because of the checking effect of the fingers H, while the plunger will not, on the other hand, be shakable into its fully seated position but will require positively applied pressure against the head 6 to reach its fully seated position.

The barrel-embracing portion 8 of the clip is preferably rounded as shown in Fig. 3, to give it greater strength. The part 8 as shown in Fig. 5 has an inner wall approximating two-thirds of the outer circumference of the barrel. This makes it possible to seat and unseat the clip with great ease, due to its resilient characteristics, and yet, by virtue of the same characteristics, to hold the clamp firmly in place on the barrel. The frictional contact face l3 of the fingers ll may be flat or shaped to fit the sides of the plunger and they may have lateral projections to increase the frictional surface, but these are details which are merely auxiliary and are therefore not illustrated.

As shown in Fig. 2 in contrast with Fig. 1, it W111 be observed that the spring fingers II, when exercising their frictional effect on the outer walls of the plunger, owe their braking effect chiefly to their own flexibility from the point where the fingers merge at a sharp angle with the portion H] of the clamp. When the camming effect takes place, however, as shown in Fig. 3, the resiliency is not only that of the fingers per se, but also that of the entire clip down to the angle where the portion 9 begins to extend away from the barrel-embracing portion 8, thereby accentuating the braking resistance of the clamp agamst movement of the plunger from its position in Fig. 1 to its fully seated position.

In view of the patent to F. L. Wood No. 2,002,024, no claim is made herein broadly to the employment of a clip which is so arranged with reference to the components of the syringe as to normally maintain the inner end of the plunger out of contact with the nozzle end of the barrel but still enables the plunger to be pushed all the way into the barrel of the syringe, but what is claimed herein is the specific and novel arrangement described hereinabove and defined by the following claims.

I claim:

1. In a syringe of the type which comprises a barrel having a nozzle end and a plunger end, a ledge projecting outwardly from the plunger end, a plunger having an enlarged head portion adapted to be pressed by the user, and clip means for maintaining the inner end of the plunger normally out of contact with the nozzle end of the barrel but yieldable to permit such contact to be made when desired, that improvement which comprises in the recited combination a clip structure of resilient material having a barrel-embracing portion seated beneath the ledge, a pair of diametrically opposed relatively flat extensions connected with said barrel-embracing portion and extending upwardly with their flat faces constantly facing the axis of the plunger to a height above the ledge greater than the height of the under side of the plunger head when the plunger is in contact with the nozzle end of the barrel, said extensions having terminals which flare outwardly from the axis of the plunger in opposite directions, all arranged so that each of said extensions with its terminal will be limited in its flexing movements to motions at right angles to the axis of the plunger and in directions opposite to that of the other extension, the extensions at their bent-back terminal portions acting as brakes against the plunger and as a means to resist complete descent of the plunger into contact with the nozzle end of the barrel except under pressure of the operator and also to return the plunger, when said pressure is released, to the position in which the plunger end is maintained out of contact with the nozzle end of the barrel. 2. The combination set forth in claim 1 in which each of the upwardly extending fiat resilient extensions is connected with the barrel-embracing portion of the clip by an integral strip which extends outwardly from the barrel beneath its ledge to form a resilient hinge, thence upwardly around the ledge and back over the top of the ledge in a direction toward the axis of the plunger whereby, as the plunger is positioned at any point intermediate of its complete stroke, the normal braking action of the upwardly rising extensions of the clip will be a function of the resilience of said portions, while, as said portions are forcibly pressed apart in the final seating movement of the plunger in the barrel, their own resilience is reinforced by the hinge connection with the barrel-embracing part of the clip, said reinforced resiliency serving as a combined force to withdraw the plunger to a position where its inner end is free from contact with the nozzle end of the barrel and where the parts are restored to the condition where thereafter the resilience of the extensions alone exercise their braking effect.

FAIRLEIGH S. DICKINSON. 

